User mode exceptions

WINDBG
1

Hi everyone,

Does anyone know how to bypass usermode exceptions in WinDBG?

Currently I am testing an interface for a driver for c# and the .net is
full of int 3. Is there a way to bypass these int 3s while still
debugging the kernel in WinDBG? (without all the annoying “gn” commands)

Cheers.

2
  1. If you’re running on S2K3+:

kdbgctrl -du

This requires that you install windbg on the target (kdbgctrl.exe is located in )

There’s also a bcd/boot.ini (maybe) setting called something like ‘noumex’ that disables these as well.

I’ve never used this option, but I think (maybe) that these will do it:

boot.ini:

/debug=noumex

bcdedit /set noumex on

2. On any platform, you can use ‘sxi’ the next time you get one and that should supress them for the rest of the session.

Now, why .NET is throwing all of these is perhaps a question you should consider before surpressing them, and I’m not really sure what will happen in user mode as a result. Depending on what you wish, you may need to add the ‘-h’ option to consider the exceptions ‘handled.’

Good luck,

mm

3

On 21/10/2009 10:18 AM, xxxxx@evitechnology.com wrote:

  1. If you’re running on S2K3+:

kdbgctrl -du

This requires that you install windbg on the target (kdbgctrl.exe is located in)
>
> There’s also a bcd/boot.ini (maybe) setting called something like ‘noumex’ that disables these as well.
>
> I’ve never used this option, but I think (maybe) that these will do it:
>
> boot.ini:
>
> /debug=noumex
>
> bcdedit /set noumex on
>
> 2. On any platform, you can use ‘sxi’ the next time you get one and that should supress them for the rest of the session.
>
> Now, why .NET is throwing all of these is perhaps a question you should consider before surpressing them, and I’m not really sure what will happen in user mode as a result. Depending on what you wish, you may need to add the ‘-h’ option to consider the exceptions ‘handled.’
>
>
>
I am running on XP. :frowning:
With the boot.ini file the “/debug=noumexz” i’ll try that now, but
“/debug, noumex” doesn’t work, I saw that somewhere on the net (msdn i
think)…
.Net throws theses as part of the debugger, every line step set theses
off, it’s the way .net debugging works.

Cheers.